The FAANGs have definitely inflated prices, but in those companies the average revenue per employee is just orders of magnitude larger than anything a physical product company can produce. Giving a software engineer 2x or 5x salary compared to embedded is literally noise on the balance sheet.
They're not you VC, SASS, zero marginal cost software first company. They're hardware manufacturers with physical product margins. The embedded project I work on only ships on a few thousand units/year, and it's only a small component of the overall system.
I think within that group of companies, the comp for embedded vs "software" isn't significantly different. "Software" just has FANG/VC backed salary inflation making the averages look crazy.